1. Field of the Invention
This invention relates to a ferroelectric liquid crystal device such as a liquid crystal display device or a liquid crystal-optical shutter array, etc., more particularly to a ferroelectric liquid crystal device having a color filter improved in display and driving characteristics by obtaining a liquid crystal phase of uniform mono-domain without alignment defect through improvement of the initial alignment state of liquid crystal molecules.
2. Related Background Art
Liquid crystal devices known in the art may be, for example, those using twisted nematic crystal as disclosed in M. Schadt and W. Helfrich, "Applied Physics Letters", vol. 18, No. 4 (published on Feb. 15, 1971), p. 127-128, "Voltage Dependent Optical Activity of a Twisted Nematic Liquid Crystal". The TN liquid crystal, which involves the problem of generating crosstalk during time divisional driving by use of a matrix electrode structure with increased picture element density, has been limited in number of picture elements.
Also, a display device of the system in which switching elements with thin film transistors are connected with the respective picture elements and each picture element is subjected to switching has been known, but the step of forming thin film transistors on a substrate is extremely complicated and furthermore there is the problem that a display device with a large area can be prepared with difficulty.
As the device solving these problems, Clark et al. proposed a ferroelectric liquid crystal device in U.S. Pat. No. 4,367,924.
This ferroelectric liquid crystal device is generally called Surface Stability Ferroelectric Liquid Crystal (SSFCC), and is set at a sufficiently thin film thickness (e.g., 1 to 2 .mu.m) in order to unwind the spiral structure inherently possessed by the chiral smectic liquid crystal. According to Unexamined Japanese Patent Publication No. 147232/1986 of Tsuboyama, it has been clarified that when there is a stepped difference of 1000 .ANG. or more within the substrate plane used in the cell forming SSFLC, an alignment defect portion will be generated around a stepped portion.
Whereas, for applying the aforementioned ferroelectric liquid crystal device to color display, it may be conceivable to arrange a color filter within the cell.
In general, a color filter is a structure of a group of color filter units (each being one R, G or B filter) of red color (R) , green color (G) and blue color (B) arranged in a stripe or mosaic shape. Since each color filter unit is formed of a resin film colored into R, G or B, there occurred a stepped difference of about 2000 .ANG. to 1 .mu.m within the substrate plane when such color filters were arranged within the cell.